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Message-ID: <CAHp75VcefOJHZ3WdZYrGEJFjqg2s1oJ75Jg9gKmQFre_ScAPZg@mail.gmail.com>
Date: Fri, 19 Oct 2018 19:06:56 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Lubomir Rintel <lkundrak@...sk>
Cc: Mark Brown <broonie@...nel.org>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Darren Hart <dvhart@...radead.org>,
Andy Shevchenko <andy@...radead.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
quozl@...top.org, Sebastian Reichel <sre@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Eric Miao <eric.y.miao@...il.com>,
Haojian Zhuang <haojian.zhuang@...il.com>,
Daniel Mack <daniel@...que.org>,
Robert Jarzmik <robert.jarzmik@...e.fr>,
linux-spi <linux-spi@...r.kernel.org>,
devicetree <devicetree@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
Platform Driver <platform-driver-x86@...r.kernel.org>,
devel@...verdev.osuosl.org, Linux PM <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 06/15] Platform: OLPC: Add XO-1.75 EC driver
On Wed, Oct 10, 2018 at 8:24 PM Lubomir Rintel <lkundrak@...sk> wrote:
>
> It's based off the driver from the OLPC kernel sources. Somewhat
> modernized and cleaned up, for better or worse.
>
> Modified to plug into the olpc-ec driver infrastructure (so that battery
> interface and debugfs could be reused) and the SPI slave framework.
> +#include <asm/system_misc.h>
asm/* goes after linux/*
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/spinlock.h>
> +#include <linux/completion.h>
> +#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +#include <linux/ctype.h>
> +#include <linux/olpc-ec.h>
> +#include <linux/spi/spi.h>
> +#include <linux/reboot.h>
> +#include <linux/input.h>
> +#include <linux/kfifo.h>
> +#include <linux/module.h>
> +#include <linux/power_supply.h>
Easy to maintain when it's sorted.
> + { 0 },
Terminators are better without trailing comma.
> +#define EC_CMD_LEN 8
> +#define EC_MAX_RESP_LEN 16
> +#define LOG_BUF_SIZE 127
127 sounds slightly strange. Is it by specification of protocol? Would
it be better to define it 128 bytes / items?
> +static int olpc_xo175_ec_is_valid_cmd(u8 cmd)
> +{
> + const struct ec_cmd_t *p;
> +
> + for (p = olpc_xo175_ec_cmds; p->cmd; p++) {
> + if (p->cmd == cmd)
> + return p->bytes_returned;
> + }
> +
> + return -1;
-EINVAL ?
> +}
> +static void olpc_xo175_ec_complete(void *arg);
Hmm... Can we avoid forward declaration?
> + channel = priv->rx_buf[0];
> + byte = priv->rx_buf[1];
Maybe specific structures would fit better?
Like
struct olpc_ec_resp_hdr {
u8 channel;
u8 byte;
...
}
> + dev_warn(dev, "kbd/tpad not supported\n");
Please, spell it fully as touchpad and keyboard.
> + pm_wakeup_event(priv->pwrbtn->dev.parent, 1000);
Magic number.
> + /* For now, we just ignore the unknown events. */
dev_dbg(dev, "Ignored unknown event %.2x\n", byte);
?
> if (isprint(byte)) {
> + priv->logbuf[priv->logbuf_len++] = byte;
> + if (priv->logbuf_len == LOG_BUF_SIZE)
> + olpc_xo175_ec_flush_logbuf(priv);
> + }
You may consider to take everything and run %pE when printing instead of %s.
> +static int olpc_xo175_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *resp,
> + size_t resp_len, void *ec_cb_arg)
> +{
> + struct olpc_xo175_ec *priv = ec_cb_arg;
> + struct device *dev = &priv->spi->dev;
> + unsigned long flags;
> + int nr_bytes;
> + int ret = 0;
> +
> + dev_dbg(dev, "CMD %x, %d bytes expected\n", cmd, resp_len);
> +
> + if (inlen > 5) {
Magic number.
> + dev_err(dev, "command len %d too big!\n", resp_len);
> + return -EOVERFLOW;
> + }
> + WARN_ON(priv->suspended);
> + if (priv->suspended)
if (WARN_ON(...)) ?
> + return -EBUSY;
> + if (resp_len > nr_bytes)
> + resp_len = nr_bytes;
resp_len = min(resp_len, nr_bytes);
> + priv->cmd[0] = cmd;
> + priv->cmd[1] = inlen;
> + priv->cmd[2] = 0;
Perhaps specific struct header for this?
> + memset(resp, 0, resp_len);
Wouldn't be better to do this in where actual response has been filled?
> + if (!wait_for_completion_timeout(&priv->cmd_done,
> + msecs_to_jiffies(4000))) {
Magic number.
> + }
> + /* Deal with the results. */
Somehow feels noisy / unneeded comment.
> + if (priv->cmd_state == CMD_STATE_ERROR_RECEIVED) {
> + /* EC-provided error is in the single response byte */
> + dev_err(dev, "command 0x%x returned error 0x%x\n",
> + cmd, priv->resp[0]);
Indentation.
> + ret = -EREMOTEIO;
> + } else if (priv->resp_len != nr_bytes) {
> + dev_err(dev, "command 0x%x returned %d bytes, expected %d bytes\n",
> + cmd, priv->resp_len, nr_bytes);
> + ret = -ETIMEDOUT;
In the message I see nothing about timeout.
> + } else {
> + }
> +}
> +static int olpc_xo175_ec_set_event_mask(unsigned int mask)
> +{
> + unsigned char args[2];
u8
> +
> + args[0] = mask & 0xff;
> + args[1] = (mask >> 8) & 0xff;
...mask >> 0;
...mask >> 8;
> + return olpc_ec_cmd(CMD_WRITE_EXT_SCI_MASK, args, 2, NULL, 0);
> +}
> +
> +static void olpc_xo175_ec_restart(enum reboot_mode mode, const char *cmd)
> +{
> + while (1) {
> + olpc_ec_cmd(CMD_POWER_CYCLE, NULL, 0, NULL, 0);
> + mdelay(1000);
> + }
> +}
> +
> +static void olpc_xo175_ec_power_off(void)
> +{
> + while (1) {
> + olpc_ec_cmd(CMD_POWER_OFF, NULL, 0, NULL, 0);
> + mdelay(1000);
> + }
> +}
> +
> +#ifdef CONFIG_PM
> +static int olpc_xo175_ec_suspend(struct device *dev)
__maybe_unused instead of ugly #ifdef?
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct olpc_xo175_ec *priv = platform_get_drvdata(pdev);
dev_get_drvdata() or how is it called?
> + unsigned char hintargs[5];
struct olpc_ec_hint_cmd {
u8 ...
u32 ...
};
?
> + static unsigned int suspend_count;
u32 I suppose.
> +
> + suspend_count++;
> + dev_dbg(dev, "%s: suspend sync %08x\n", __func__, suspend_count);
__func__ can be issued if user asked for via Dynamic Debug interface.
> + /*
> + * First byte is 1 to indicate suspend, the rest is an integer
> + * counter.
> + */
> + hintargs[0] = 1;
> + memcpy(&hintargs[1], &suspend_count, 4);
> + olpc_ec_cmd(CMD_SUSPEND_HINT, hintargs, 5, NULL, 0);
What do you need this counter for?
> + priv->suspended = true;
Hmm... Who is the user of it?
> + return 0;
> +}
> +
> +static int olpc_xo175_ec_resume_noirq(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct olpc_xo175_ec *priv = platform_get_drvdata(pdev);
> +
> + priv->suspended = false;
> +
> + return 0;
> +}
> +
> +static int olpc_xo175_ec_resume(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct olpc_xo175_ec *priv = platform_get_drvdata(pdev);
> + unsigned char x = 0;
u8
> + priv->suspended = false;
Isn't it redundant since noirq callback above?
> + /*
> + * The resume hint is only needed if no other commands are
> + * being sent during resume. all it does is tell the EC
> + * the SoC is definitely awake.
> + */
> + olpc_ec_cmd(CMD_SUSPEND_HINT, &x, 1, NULL, 0);
> +
> + /* Enable all EC events while we're awake */
> + olpc_xo175_ec_set_event_mask(0xffff);
#define EC_ALL_EVENTS GENMASK(15, 0)
> +}
> +#endif
> +static struct platform_device *olpc_ec;
I would rather see this at the top of file.
> +static int olpc_xo175_ec_probe(struct spi_device *spi)
> +{
> + if (olpc_ec) {
> + dev_err(&spi->dev, "OLPC EC already registered.\n");
> + return -EBUSY;
> + }
It's racy against parallel probe called. I don't think it would be a
real issue, just let you know.
> + /* Set up power button input device */
> + priv->pwrbtn = devm_input_allocate_device(&spi->dev);
> + if (!priv->pwrbtn)
> + return -ENOMEM;
> + priv->pwrbtn->name = "Power Button";
> + priv->pwrbtn->dev.parent = &spi->dev;
> + input_set_capability(priv->pwrbtn, EV_KEY, KEY_POWER);
> + ret = input_register_device(priv->pwrbtn);
> + if (ret) {
> + dev_err(&spi->dev, "error registering input device: %d\n", ret);
> + return ret;
> + }
I would split out power button driver, but it's up to you.
> + /* Enable all EC events while we're awake */
> + olpc_xo175_ec_set_event_mask(0xffff);
See above about this magic.
> +}
> +#ifdef CONFIG_PM
> + .suspend = olpc_xo175_ec_suspend,
> + .resume_noirq = olpc_xo175_ec_resume_noirq,
> + .resume = olpc_xo175_ec_resume,
> +#endif
SET_SYSTEM_SLEEP_PM_OPS() ?
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() ?
> +static const struct of_device_id olpc_xo175_ec_of_match[] = {
> + { .compatible = "olpc,xo1.75-ec" },
> + { },
No comma for terminators.
> +};
--
With Best Regards,
Andy Shevchenko
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